1. Field of the Invention
This invention relates to a method for preparing pulverized Polydextrose having a particle size of under about 125 microns in diameter. More particularly, the improved method comprises admixing Polydextrose which is substantially free of low molecular weight organic acids with an anti-caking agent and pulverizing the mixture to form the pulverized Polydextrose. The pulverized Polydextrose may be used in a variety of chewing gum products and edible products. The present invention also pertains to methods for preparing the chewing gum and edible products in which the novel pulverized Polydextrose may be used.
2. Description of the Prior Art
Polydextrose is a water-soluble, low-calorie, non-cariogenic bulking agent which contributes the bulk and texture normally associated with sugars in many food products. Polydextrose is a randomly bonded glucose polymer prepared by polymerizing glucose and/or maltose by anhydrous melt polymerization techniques using nonvolatile, edible, organic polycarboxylic acids and polyols as catalysts, cross-linking agents and/or polymerization activators. Procedures for preparing Polydextrose are disclosed in U.S. Pat. Nos. 3,766,165 and 3,876,794, issued to Rennhard.
Polydextrose is a low-calorie sugar substitute (containing about 1 calorie/gram) which has many of the technological properties of sugar without the sweetness. This non-sweet bulking agent is especially useful when used in combination with high intensity sweeteners to provide low-calorie food products having the desirable texture of conventional sugar-containing food products without the calories associated with such products.
Polydextrose is commercially available in three forms: Polydextrose A, an amorphous, slightly acidic (pH of 2.5-3.5) fusible powder; Polydextrose N, a potassium hydroxide partially neutralized (pH of 5-6) light-colored 70% aqueous solution of Polydextrose A; and Polydextrose K, a potassium bicarbonate partially neutralized (pH of 5-6) powder form of Polydextrose A.
All of these Polydextrose products contain quantities of unreacted monomers, such as glucose, sorbitol, as well as citric acid, 1, 6-anhydroglucose (levoglucosan) and 5-hydroxymethylfurfural. For example, the amount of citric acid (or citric acid salts) present in Polydextrose is about 0.9%, by weight. The presence of these impurities gives Polydextrose a bitter off-taste and/or musty off-flavor and limits the quantity of Polydextrose which can be used as a bulking agent in food products.
Polydextrose has recently become available in a fourth form: Improved Polydextrose, a form of Polydextrose A which is substantially free of certain low molecular weight organic acids (pH of 3-4) wherein the acids are present in the bulking agent in an amount of less than about 0.3%, by weight. While removal of these low molecular weight acids helps to eliminate the off taste associated with Polydextrose, the absence of these acids in the bulking agent makes Improved Polydextrose difficult to handle. For example, Improved Polydextrose is a coarser material, and contains more static charge, than Polydextrose A. This increase in static charge presumably results from removing the low molecular weight organic acids from Polydextrose A which may act as static charge neutralizers or stabilizers.
Because of the coarseness of Improved Polydextrose, only a small amount of this form of Polydextrose can be added as a bulking agent to a foodstuff (for instance, only about 10-15% in a chewing gum composition) due to the gritty texture of the bulking agent and the resulting non-uniform distribution of the other components in the foodstuff. Furthermore, this coarse form of Improved Polydextrose cannot be readily pulverized into a fine form to permit larger amounts of Improved Polydextrose to be added to a foodstuff because of the static charge in the bulking agent.
Polydextrose Research Product Bulletin, Pfizer, Central Research, Groton, Connecticut (1981), p. 11 discloses that a chewing gum composition can be prepared by micronizing a mixture of Polydextrose A, sodium bicarbonate, sorbitol and an intense sweetener and then adding the milled mixture to a melted gum base mixture.
U.S. Pat. No. 4,382,963, issued to Klose et al. and assigned to General Foods Corporation, discloses a low-calorie, sugar-free chewing gum composition containing as the sole bulking agent Polydextrose N as a spray-dried powder.
U.S. Pat. No. 4,765,991, issued to Cherukuri et al. and assigned to Warner-Lambert Company, discloses a reduced calorie chewing gum composition comprising a high percentage of a non-styrene-butadiene copolymer/polyvinyl acetate elastomer chewing gum base and a small percentage of a polysaccharide selected from the group consisting of Polydextrose, polymaltose, modified Polydextrose, and mixtures thereof.
U.S. Pat. No. 4,622,233, issued to Torres, and U.S. patent application Ser. Nos. 043,793 and 193,961, both of which are assigned to Warner-Lambert Company, disclose methods for purifying Polydextrose.
While the above methods provide foodstuff compositions which contain some form of Polydextrose, none of the above disclosures has overcome the problem of providing a Polydextrose composition which is substantially free of low molecular weight organic acids and which is sufficiently fine in texture such that the Polydextrose composition can be used as the sole bulking agent. Thus it would be commercially advantageous to furnish a method for preparing pulverized substantially acid-free Polydextrose to provide a sugar substitute for foodstuff compositions. Such a method would permit a food product to contain only Polydextrose as the bulking agent without an off-taste or gritty texture and would result in a significant reduction in caloric intake. The present invention provides a method for preparing such an improved pulverized Polydextrose product without the disadvantages characteristic of previously known products. The pulverized Polydextrose product has improved taste and texture and may be used in a variety of sugarless and sugared reduced-calorie chewing gum compositions and food products. The present invention also pertains to methods for preparing sugarless and sugared chewing gum compositions and food products in which the inventive composition may be used.